In October 2012 U.S. Border Patrol officers shot and killed 16-year-old Jose Antonio Elena Rodriguez with 10 bullets as he walked down a street in the border city of Nogales, Mexico. Today, the ACLU filed a lawsuit in U.S. District Court on his mother Araceli Rodriguez's behalf against the agency which it says operates with impunity.

"The U.S. Border Patrol agents who killed my son in a senseless act of violence are still out there and they need to be brought to justice," said Araceli Rodriguez in a statement. "The U.S. government has not held the agents who shot my son accountable and that is why I am bringing this lawsuit."

Border Patrol officers have killed dozens of migrants in recent years, and advocates say that those deaths have highlighted the agency's lax use of force guidelines. Since 2005, Border Patrol officers have been involved in the deaths of at least 42 people, according to the ACLU. Fifteen of those deaths occurred in between 2011 and 2012. This spring, the agency "tightened" its rules of engagement for its officers, The Arizona Republic reported.

Still, said ACLU Immigrants' Rights Project attorney Lee Gelernt in a statement, "Jose Antonio's death is unfortunately not unique. Border Patrol is using excessive and unnecessary force against people on both sides of the border. Agents continue to violate the Constitution with impunity."